It's the latest in a string of setbacks for a Niners squad that has seen key players sidelined almost weekly. Tight end George Kittle (hamstring) and quarterback Brock Purdy (toe) went down in Week 1, followed by wide receiver Jauan Jennings (shoulder, ankle) and guard Ben Bartch (ankle) in Week 2 against New Orleans.
Bosa's misfortune came late in the first quarter when he charged Cardinals quarterback Kyler Murray off the edge. While locked up with left tackle Kelvin Beachum, he was hit by guard Evan Brown on a double team, sending him to the turf and ultimately out for the season.
This isn't the first time Nick Bosa has had to tackle such a grueling road back. He previously tore his left ACL just two games into the 2020 season. That setback didn't hold him down for long, as he came back the very next year to play all 17 contests and rack up an impressive 15.5 sacks.
His recovery will again be closely tracked throughout the upcoming offseason. Even with this latest blow, Bosa should still be firmly in his prime when he turns 28 and takes the field for the 2026 campaign.